Cooling unit



Feb. 18, 1941. I w. SPOFFORD 2,232,568

COOLING UNIT Filed Feb 27, 1940 -Zla i M 1| Inventor Warren A. 5poff0rd,

lay/V4447 His Attorney.

Patented Feb. 18, 1941 PATENT OFFICE COOLING UNIT Warren A. Spofford, Glen Ridge, N. 1., assignor to General Electric Company, a corporation of New York Application February 27, 1940, Serial No. 321,631 4 Claims. (oi. 62-126) My invention relates to cooling units, and par ticularly to cooling units having a plurality of evaporating elements or conduits supplied from a single source of refrigerant, and is an improve- 5 ment over the invention disclosed and claimed in a copending application of Rollin H. Norris, Serial No. 321,029, filed Feb. 27, 1940, and assigned tothe same assignee asthe present invention.

In air conditioning systems and-in other applications of refrigerating machines, it frequently becomes necessary to supply a plurality of evaporatingtubes or elements from a single source of refrigerant. The refrigerant is supplied under control of an expansion valve and enters the evaporator as a mixture of liquid and gaseous refrigerant. When a plurality of evaporating elements are arranged in a single air stream, it has beenfound necessary to provide some arrangement for assuring substantially uniform distribution'of both liquid and gaseous refrigerant to the several evaporating elements so that all the elements will carry substantially equal loads. Accordingly, it is an object of my invention to provide a cooling unit having a plurality of evaporating elements and an improved arrangement for facilitating the uniform distribution of both liquid and gaseous refrigerant to the several elements. s

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention,

reference may be had to the accompanying drawing in which Fig. 1 illustrates diagrammatically I a refrigerating machine for an air conditioning 40 system having a cooling unit embodying my invention; and Fig. 2 is an enlarged side elevation view partly in section of the cooling unit shown I in Fig. 1. I

The refrigerating system shown in the drawing comprises essentially a motor driven compressor, a condenser for liquefying the refrigerant, and a cooling unit arranged in a stream of fluid or other mediumto be cooled, the flow of refrigerant to the cooling unit being controlled by a single expansion valve. The cooling unit itself comprises a plurality of evaporator elements one of which is provided with internal baflles and is arranged as a distributor for facilitating the even distribution of liquid'and gaseous refrigerant to the remaining elements.

Referring now to the drawing, in Fig. 1 I have shown aduct or casing ill of an air conditioning system, provided with a cooling unit ll having a plurality of refrigerant evaporating elements I2 arranged in the path of the air stream, the lowermost of the elements being designated l2a. Vaporized Irefrig erant is withdrawn from the cooling unit ll through a suction line i3 by operation of a compressor l4 driven by a motor IS. The withdrawn refrigerant is compressed and discharged by the compressor into a condenser I6 where it is cooled and liquefied, the liquid refrigerant collecting in a receiver ll. From the receiver II the liquid refrigerant is returned to the cooling unit ll under control of 15 a thermostatic expansion valve l8 having a ther-" mal element or feeler bulb I9. secured in heat exchange relation with the suction line [3 adjacent the discharge end of the cooling unit ll.

The liquid refrigerant within the cooling unit ll 20 is evaporated in the several elements i2 and Ma by the absorption of heat from the air passing through the duct Ill to be cooled. The vaporized refrigerant collects in a discharge or suction manifold 20 from which it enters the suction 25 line I3.

The lowermost element I20, is arranged to perform the function of a distributor for assuring the uniform distribution of auniform mixture of liquid and gaseous refrigerant to the evaporating elements l2. In order to accomplish this purpose, the lowermost element is provided with a plurality of outlets 2| at one end thereof and preferably equally spaced and in horizontal'alignment and which are connected to the 35 inlets of the evaporating elements I2 by conduits 2ia. A mixture of liquid and gaseous refrigerant flowing from the expansion valve I8 is admitted to the'evaporati g element l2a through an inlet connection 22' emote from the several 40 outlets 2!. A portion of the liquid refrigerant in the mixture flowing through the lowermost evapcrating element is vaporized by the absorption of heat from the air flowing over the external surfaces of the element, and since the inlets 45 and outlets of the evaporator are spaced apart the length of the evaporator, the velocity efiects due to the discharge of refrigerant from the connection 22 are minimized at the outlets and both the liquid and gaseous components of the 5 mixture tend to be distributed evenly to the several outlets. This even distribution of liquid and gaseous refrigerant is further facilitated by a plurality of internal baflles or heat transfer elements 23 arranged in the path of the refrigerant between the inlet and outlets of the evaporating element l2a. The heat transfer elements 23 have been illustrated as a plurality of wires or pins penetrating the sheets of metal constituting the Walls of the evaporating elements l2 and I20, and provide both external and internal heat transfer fins or extended surfaces. A heat transfer element of this type is described and claimed in a copending application of William Dalton and Rollin H. Norris, Serial No. 292,440, filed August 29, 1939, and assigned to the same assignee as the present application, I do not, therefore, claim herein anything described or claimed in the aforesaid Dalton and Norris application. The

outlets of the evaporating elements l2 other than the lowermost evaporating elements l2a, are all connected to the suction manifold 20, and these remaining elements are, therefore, connected in parallel between the element In and the suction manifold. Since substantially equal quantitles of liquid and gaseous refrigerant are supplied to the several evaporating elements I! through the conduits Zia, the loads carried by these elements are substantially equal. Furthermore, the load carried by each of the evaporating elements I2 is not materially different from that of the lowermost element I2a, since the velocities of the refrigerant gas in the several elements l2 and in the element In are of the same order of magnitude.

All of the evaporating elements [2 and Ma have been illustrated as of identical construction, each comprising thin, flat plates 24 and 25 bent to provide the two halves of the thin flat conduit and provided with flanges welded or otherwise suitably sealed together about their edges, the ends of the conduit being closed by suitable end plates or connections 26 inserted between the plates 24 and 25 at their ends and welded or otherwise suitably secured thereto and to the inlet and outlet connections of the cooling unit.

From the foregoing, it will readily be apparent that I have provided a cooling unit having an arrangement for facilitating the even distribution of both liquid and gaseous refrigerant to a plurality of evaporating elements which is of simple and rugged construction, and which avoids the necessity of providing a distributing header or similar device externally of the cooling unit. Furthermore, the distributing element is built into the unit and it is connected in a manner similar to that of the evaporating elements.

While I have described my invention in connection with a cooling unit for an air conditioning system, other applications will readily be apparent to those skilled in the art. I do not, therefore, desire my invention to be limited to the particular construction illustrated and described, and I intend in the accompanying claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A cooling unit for a refrigerating system comprising a plurality of heat exchange elements, one of said elements having an inlet and a plurality of outlets remote from said inlet, each of the remaining ones of said elements having an inlet and an outlet, an outlet for said cooling unit communicating with the outlets of said remaining elements, means including said plurality of outlets of said one element for connecting a plurality of said remaining elements in parallel between said one element and said outlet of said unit to supply said remaining elements with refrigerant from said one element, and bafiie means in said one element in the path of flow of refrigerant between the inlet thereof and said plurality of outlets for producing substantially uniform flow of a mixture of liquid and gaseous refrigerant from said one element through all of said plurality of outlets.

2. A cooling unit for a refrigerating system comprising a plurality of heat exchange elements, one of said elements having a thin fiat passage therein and having an inlet at one end and a plurality of outlets at the other end of said passage, each of the remaining ones of said elements having an inlet and an outlet, an outlet for said cooling unit communicating with the outlets of said remaining elements, means connecting said plurality of outlets of said one element to respective ones of the inlets of a plurality of said remaining elements for conducting to said remaining elements refrigerant from said one element, and means including a plurality of heat conducting fins arranged within said passage of said one element for facilitating the uniform distribution of both liquid and gaseous refrigerant through all of said outlets of said one element.

3. A cooling unit for a refrigerating system comprising a plurality of heat exchange elements arranged for the flow thereover of a medium to be cooled, each of said elements comprising a conduit thin and flat in the direction of flow thereover .of the medium to be cooled and having a plurality of heat transfer members extending therethrough and providing extended heat exchange surfaces both internally and externally of the conduit, one of said elements having an inlet and a plurality of outlets remote from said inlet, each of the remaining ones of said elements having an inlet and an outlet, an outlet for said cooling unit for receiving refrigerant from said remainingelements, means connecting said plurality of outlets of said one element to respective ones of the inlets of a plurality of said remaining elements to conduct to said remaining elements refrigerant from said one element, the portions of said heat transfer members within said one element facilitating the even distribution of both liquid and gaseous refrigerant to all of the outlets of said one element.

4. A cooling unit for a refrigerating system comprising a plurality of heat exchange elements, one of said elements being thin and fiat and lying substantially in a horizontal plane, said one element having formed therein a thin flat passage with an inlet at one end and a. plurality of horizontally aligned outlets at the other end thereof, each of the remaining ones of said elements having an inlet and an outlet, an outlet for said cooling um't communicating with the outlets of said remaining elements, means connecting said plurality of outlets of said one element to respective ones of the inlets of a plurality of said remaining elements for conducting to said remaining elements refrigerant from said one element, and means including a plurality of heat conducting fins arranged within said passage of said one element for facilitating the uniform distribution of both liquid and gaseous refrigerant through all of said outlets of said one element.

WARREN A. SPOFFORD. 

